Many pumped storage systems, often referred to as hydropower plants, are known in the prior art. In these plants, water is stored in an upper reservoir, and is released gravitationally during periods of high electricity demand to a lower reservoir whereat a turbine is deployed to generate power. During low-cost off-peak hours when there is less demand for electricity, the water is pumped back to the upper reservoir from the lower reservoir.
In order for these pumped storage systems to be economically viable, however, large scale hydropower plants on the order of 300 MW need to be erected. Such power levels are able to be achieved only when the differential height along which the stored water has to be delivered gravitationally is at least 100 meters, and generally at least 500 m, requiring high capital costs to build retaining walls for the reservoirs and pumping systems, as well as significant operating costs for pumping the delivered water back to the upper reservoir that reduce the profitability of the pumped storage system.
Another drawback associated with hydropower plants is the high rate of water evaporation from both the upper and lower reservoirs. Also, location-specific hydropower plants can be erected only at very specific locations characterized by a suitable topographical landscape which are not necessarily in the vicinity of power lines and therefore may not be beneficial to the utility company.
It is an object of the present invention to provide a water based stored energy system that is economically viable even when the height differential along which the water is delivered is significantly less than that of prior art systems.
It is an additional object of the present invention to provide a water based stored energy system that is economically viable even when it has a relatively low power capacity.
It is an additional object of the present invention to provide a water based stored energy system that is independent of a specific topographical layout.
Other objects and advantages of the invention will become apparent as the description proceeds.